Solid state magnetic resonance is becoming increasingly valuable for analyzing biological samples such as bone, teeth and tumor tissues. One of this technique's limitations is its inherent low sensitivity to such complex samples. The major goal of this development project is to design and produce a carbon/proton doubly tuned variable temperature probe with several advanced features for specific applications towards samples such as pigment gallstones. The probe will handle larger samples with less tank circuit losses yielding more sensitivity at 2.3 tesla (100 MHz proton) field strengths. It will also be able to handle larger proton powers for complete decoupling of samples containing broadened anisotropic carbon-13 chemical shifts--a problem often found with biomedical samples. The variable temperature capability will allow highly amorphous samples to be cooled and studied under more crystaline and spectroscopically more informative conditions. NMR instruments with magnetic fields of 4.6 tesla and higher require sample spinning rates of near 8 KHz and higher. This project will thus aim at building a probe head similar to that described above that will spin optimum sized samples at spinning rates of 8 KHz.